Feed-roll mechanism for typewriters



July 26, 1955 C- B. LETTERMAN FEED-ROLL MECHANISM FOR TYPEWRITERS Filed Dec. 29, 1953 IN VEN TOR. CHARLES 8. LE TTERMAN A rroe/vsv United States Patent FEED-ROLL MECHANISM FOR TYPEWRITERS Charles B. Letterman, West Hartford, Conn., assignor to Underwood Corporation, New York, N. Y., a corporation of Delaware Application December 29, 1953, Serial No. 400,870

3 Claims. (Cl. 197-138) This invention relates to typewriting machines and more particularly to a feed-roll mechanism for holding work pieces in close contact with the cylindrical platen of such a machine.

Typewriting machines are generally provided with a set of feed-rolls resiliently held in contact with the lower portion of the platen for feeding work sheets beneath and around said platen and with a set of auxiliary feedrolls mounted to press against the upper portion of the platen. The auxiliary'feed-rolls help to hold the paper tight against the platen along the printing line and serve to guide the leading edge of the paper rearwardly so that it will not obstruct the operators vision. The auxiliary feed-rolls are commonly mounted on a bail structure which may be pulled forward to position the feedrolls forwardly of the platen when a work sheet is being inserted into the machine or swung rearwardly out of the way when erasures are being made.

When a work sheet is first inserted into the machine it is frequently necessary to square it in order that the typed lines will extend horizontally across the paper and this necessitates casting off or disengaging the lower feed-rolls and also disengaging the auxiliary feed-rolls if they have previously been moved to engaging position. The ordinary procedure in loading a typewriter involves five manual operations, as follows: (1) The bail is pulled forward to position the auxiliary feed-rolls in front of the platen; (2) the paper is inserted at the rear of the platen and the platen knob is rotated to bring the leading edge about even with the top of the platen; (3) the main feed-rolls are disengaged and the paper is squared; (4) the main feed-rolls are reengaged and (5) the bail is moved rearwardly to engage the auxiliary feed-rolls.

It is the primary object of this invention to provide a mechanism which automatically performs thefifth operation referred to above and thereby decreases the number of manual operations involved in loading a typewriter from five to four.

Additional objects, features and advantages of the invention will become apparent as the description of a preferred embodiment thereof proceeds.

Referring now to the drawings:

Figure l is an end view, partially in section, of a typewriter carriage and showing the mechanism of the present invention in normal position,

Figure 2 is a view similar to Figure l and showing the parts in their position at the time of inserting a work sheet,

Figure 3 shows the parts at the beginning of the operation for releasing the main feed-roll, and

Figure 4 shows the parts at the time the main feed-roll releasing operation has progressed slightly farther than in Figure 3.

The particular construction of the typewriter carriage is not of the essence of the present invention but same may comprise a main frame plate secured to which is a pair of end plates one of which is indicated in dot-anddash lines at 11. A cylindrical platen 12 has an axis ice " shaft 13 by means of which it is rotatably mounted the carriage end plates.

Main feed-rolls 14 are carried by arms 15 and 16 pivotally mounted on a shaft 17 carried by brackets, one of which is indicated at 18, secured to the frame plate 10. Springs 19 and 20 urge the arms 15 and 16 respectively in directions to engage the feed-rolls with the lower portion of the platen. A shaft 21 is rotatably mounted in the brackets 18 and has secured thereto a crank arm 22 by means of which said shaft may be rotated and a double edged cam 23 for pressing against the arms 15 and 16 to disengage the feed-rolls from the platen. A feed-roll release lever 24 is pivotally mounted on the axis shaft 13 and is connected by a link 25 to the crank arm 22. The release lever 24 is provided with a finger piece 26 by means of which it may be swung between feed-roll engaging position defined by the cooperation of a shoulder 27 thereon with a shaft 28 extending between the carriage end plates and feed-roll release position defined by the cooperation of a nose 29 on said lever with a pin 30 in one of the end plates 11.

Auxiliary feed-rolls 31 are carried by a bail structure comprising a rod 32 extending parallel to the platen and a pair of rearwardly extending side arms 33, only one of which is shown. The arms 33 are pivotally connected at their rear ends to the upper ends of links 34, only one of which is shown, by means of pivot pins 35. The lower ends of the links 34 are secured to the aforementioned shaft 28, said shaft being pivotally mounted in the carriage end plates. Together the links 34 and the shaft 38 constitute a rockable structure. A spring 36 is secured at one end to a pin 37 on one of the bail arms 33 and at its other end is slidably anchored in a slot 38 provided in a tab 39 secured to the carriage end plate 11.

Normally the links 34 are inclined away from the platen and are held by the spring 36 in the position shown in Figures 1 and 4 with the pivot pin 35 resting against a stop 40 provided on the end plate 11. With the links 34 in this position the auxiliary feed-rolls 31 will normally be held against the upper portion of the platen by the spring 36, as shown in full lines in Figure l, but when erasures are to be made the bail structure may be pivoted rearward about the pins 35 as indicated by chaindotted lines in Figure 1. When the bail structure is moved to the chain-dotted line position the spring 36 moves over the center of the pivot pin 35 to hold it in that position, a tab 41 on one of the arms 33 contacting the rear edge of one of the links 34.

The upper end of the feed-roll release lever 24 is offset from the lower end, a shoulder 42 being formed at the point of offset. Should it be desired to release thepaper from the action of the feed-rolls when both sets of feed-rolls are in active position, the operator need only pull forward on the lever 24 and as the main feed-rolls become released the shoulder 42 presses against the lower edge of the bail arm 33 to swing the bail upwardly far enough to release the auxiliary feed-rolls, as shown in Figure 4. When the lever 24 is moved back to normal position to allow the main feed-rolls to reengage the platen, the auxiliary feed-rolls are reengaged by the spring 36.

When the machine is to be loaded, that is, when a sheet of paper is to be inserted, the operator pulls the auxiliary feed-roll bail forward, a finger piece 43 being provided for this purpose. When the finger piece 43 is moved forward, the rockable structure including the links 34 moves over center and becomes inclined toward the platen, as shown in Figure 2, the pivot pin 35 at that time contacting a stop 44 provided on the carriage end plate 11. A pin 43 is provided in the carriage end plate 11 and normally lies within a recess provided in the lower edge of the bail arm 33 and out of contact with With the parts in the Figure 2 position, the pull of the spring 36 is parallel to the links 34 and only slightly forward of the pivot pins 35. The auxiliary feed-roll system comprising the hail, the rockable structure and the spring is therefore almost in balance and the pin 35 rests lightly against the stop 44. Only a slight rearward movement of the pin 35 is required to allow the spring 36 to snap the rockable structure including the links 34 rearward against the stops 40. When the operator now pulls forward on the feed-roll release lever 24 to disengage the main feed-roll preparatory to squaring the paper, the shoulder 42 strikes the lower edge of the bail arm 33, as shown in Figure 3, and the pressure on the pin 45 is thereby transferred to said shoulder. This is enough to upset the balance of the auxiliary feed-roll system and swing the pivot pins 35 over center or sufliciently near to over center that the spring will snap the bail system from the Figure 3 position to the Figure 4 position. Since the arm 33 is resting on the shoulder, the feed-rolls 31 will be held out of engagement with the platen as long as the release lever is in its forward position. When the lever 24 is moved rearward to allow the main feed-rolls to reengage, the spring 36 pulls the auxiliary feed-rolls into engagement with the upper portion of the platen.

Thus with the device of the present invention, it is.

not necessary for the operator to manually reengage the auxiliary feed-rolls after inserting and squaring the papery This operation is performed automatically during the operations of the feed-roll release lever 24.

Having thus described the invention, what is claimed is: 1.'In a typewriting machine, a carriage frame and a cylindrical platen rotatably mounted thereon, a rockable structure pivotally mounted on said carriage frame rearwardly of said platen, a bail comprising side arms pivoted on said rockable structure and a connecting rod securing said arms together, an auxiliary feed-roll carried by said connecting rod and adapted to press against the upper portion of said platen, said rockable structure being movable from a rearwardlyinclined position wherein said feed-roll is above said platen to a forwardly inclined position wherein said feed-roll is forward of said platen, resilient means holding said rockable structure in either of its inclined positions, main feed-rolls spring urged into engagement with the lower portion of said platen, a feed-roll release lever operatively connected to said main feed-rolls and movable from a feed-roll engaging position to a feed-roll release position, and means on said release lever engaging said bail when said release lever is moved to feed-roll release position to cause said resilient means to move said rockable structure to its rearwardly inclined position if at that time said structure is in its forwardly inclined position.

2. In a typewriting machine, a carriage frame and a cylindrical platen rotatably mounted thereon, a rockable structure pivotally mounted on said carriage frame rearwardly of said platen, a bail comprising side arms pivoted on said rockable structure and a connecting rod securing said arms togethenan auxiliary, feed-roll carried by said connecting rod and adapted to press against the upper portion of said platen, said rockable structure being movable from a rearwardly inclined position wherein said feed-roll is above said platen to a forwardly inclined position wherein said feed-roll is forward of said platen, a spring connected to said bail and holding said rockable structure in either of its inclined positions, main feedrolls spring urged into engagement with the lower portion of said platen, a feed-roll release lever operatively connected to said main feed-rolls and movable from a feed-roll engaging position to a feed-roll release position, and means on said release lever engaging said bail when said release lever is moved to feed-roll release position to cause said spring to move said rockable structure to its rearwardly inclined position if at that time said structure is in its forwardly inclined position, said means holding said auxiliary feed-roll off the platen while said release lever is in feed-roll release position and said spring moving said auxiliary feed-roll into engagement with said platen when said release lever is returned to feed-roll engaging position.

3. In a typewriting machine, a carriage frame and a cylindrical platen rotatably mounted thereon, a rockable structure pivotally mounted on said carriage frame rearwardly of said platen, a bail comprising side arms extending transversely of said platen and a connecting rod securing said side arms together, an auxiliary feed-roll mounted on said connecting rod, said side arms being' pivotally connected at their rear ends to said rockable structure, said rockable structure having two stop positions, in one of which positions said rockable structure is inclined rearwardly away from the platen and in the other of which positions said structure is inclined toward the platen, a spring urging said bail about its pivotal connection with said rockable structure in a direction to engage said auxiliary feed-roll with the platen, said spring also serving to resiliently, hold said rockable structure in either of its inclined positions to which it may be moved, the rearwardly inclined position of said structure locating said auxiliary feed-roll to bear against the upper portion of the platen and the forwardly inclined position of said structure locating said feed-roll forward 1 of the platen, means to hold said auxiliary feed-roll out of contact with the platen when it is in its forward position, said forward position placing the rockable structure close to a balanced condition wherein an upset of the balance will cause said spring to snap said structure and said bail rearwardly, a set of main feed-rolls spring urged into engagement with the lower portion of said platen, a main feed-roll release lever operatively connected to said main feed-rolls and movable between a feed-roll engaging position and a feed-roll release position, and means on said release lever for upsetting the balance of said rockable structure when said release lever is moved to its feed-roll release position.

References Cited in the file of this patent UNITED STATES PATENTS 1,508,836 Degener Sept. 16, 1924 2,131,149 Smith Sept. 27, 1938 2,142,245 Helmond Jan. 3, 1939 

